Archive for wikipedia

Privacy-preserving Computing [book review]

Posted in Books, Statistics with tags , , , , , , , , , , , , , , on May 13, 2024 by xi'an

Privacy-preserving Computing for Big Data Analytics and AI, by Kai Chen and Qiang Yang, is a rather short 2024 CUP book translated from the 2022 Chinese version (by the authors).  It covers secret sharing, homomorphic encryption, oblivious transfer, garbled circuit, differential privacy, trusted execution environment, federated learning, privacy-preserving computing platforms, and case studies. The style is survey-like, meaning it often is too light for my liking, with too many lists of versions and extensions, and more importantly lacking in detail to rely (solely) on it for a course. At several times standing closer to a Wikipedia level introduction to a topic. For instance, the chapter on homomorphic encryption [Chap.5] does not connect with the (presumably narrow) picture I have of this method. And the chapter on differential privacy [Chap.6] does not get much further than Laplace and Gaussian randomization, as in eg the stochastic gradient perturbation of Abadi et al. (2016) the privacy requirement is hardly discussed. The chapter on federated leaning [Chap.8] is longer if not much more detailed, being based on a entire book on Federated learning whose Qiang Yang is the primary author. (With all figures in that chapter being reproduced from said book.)  The next chapter [Chap.9] describes to some extent several computing platforms that can be used for privacy purposes, such as FATE, CryptDB, MesaTEE, Conclave, and PrivPy, while the final one goes through case studies from different areas, but without enough depth to be truly formative for neophyte readers and students. Overall, too light for my liking.

[Disclaimer about potential self-plagiarism: this post or an edited version will eventually appear in my Books Review section in CHANCE.]

Wikileech

Posted in University life with tags , , , , , , , , on March 17, 2024 by xi'an

Another type of email hassling (or scam?), not asking for payment at this early stage for writing my Wikipedia page for me!, which is going against the rules of the platform:

My name is dah and I work with Wiki-blah, a Wikipedia page creation and management firm. In a quick Google search of your name, I discovered that you do not have a Wikipedia page.

Having a Wikipedia page shows the world that you have made remarkable contributions in your field. Moreover, it catalogues all of your important work in one place, making it easier for the reader to understand your work. Over 73% people searching for an academic on Google visit the academic’s Wikipedia page first and their official university page later. This underscores an important fact: the credibility of Wikipedia surpasses that of your official website. With over 3000 articles declined from Wikipedia everyday, it is not easy to get a Wikipedia page. However, we can make the process very easy for you. We have written Wikipedia pages for over a thousand academics. We can write one for you. For your assurance and safety, we don’t request any upfront payment.

Please send me a message if you would like to find out more about working with us.

And a second one came the day after, in a much more flowery style that omitted any mention of payment:

I trust this message finds you in great health and high spirits.

I’m dah, I am a part of a group of Wikipedia Administrators and Editors, driven by a passion for crafting impactful narratives. With over a decade of experience, our focus lies in assisting individuals and businesses like yours in establishing a lasting presence on Wikipedia, the world’s foremost information platform.

Have you ever considered having your accomplishments and contributions showcased on the influential stage of Wikipedia? I specialize in navigating the intricacies of Wikipedia’s guidelines, ensuring your story meets the stringent standards set by the platform. What sets our approach apart is the inherent resilience of entries created under the supervision of a Wikipedia Administrator – they stand stronger against scrutiny and time. We understand the unique challenges of getting pages published on Wikipedia. We have a proven track record of successfully guiding experts like yourself through the process. By collaborating, we can not only ensure the accurate portrayal of your journey but also secure its place in the annals of Wikipedia’s knowledge repository.

Understanding the complexities of Wikipedia’s communal editing and content standards can be daunting. This is where our expertise shines. As Wikipedia Administrators, we have the ability to guide your entry through the labyrinth of guidelines, maintaining the utmost standards of neutrality and credibility.
If you’re intrigued by the prospect of immortalizing your story on Wikipedia, I’m excited to explore this opportunity further. I’d be happy to share a recent success story or provide a testimonial upon your request. Feel free to reach out with any queries or curiosities you may have. Your achievements deserve a platform that resonates with millions of global readers.

I would love to discuss this opportunity further at your earliest convenience. I look forward to potentially collaborating on this remarkable journey.

Libé on Wikipédia [cover]

Posted in Books, Kids, pictures with tags , , , , , , on November 20, 2022 by xi'an

ABC for COVID spread reconstruction

Posted in Books, pictures, Statistics, Travel with tags , , , , , , , , , on December 27, 2021 by xi'an

A recent Nature paper by Jessica Davis et al. (with an assessment by Simon Cauchemez and X from INSERM) reassessed the appearance of COVID in European and American States. Accounting for the massive under-reporting in the early days since there was no testing. The approach is based on a complex dynamic model whose parameters are estimated by an ABC algorithm (the reference being the PLoS article that initiated the ABC Wikipedia page). Results are quite interesting in that the distribution of the entry dates covers a calendar as early as December 2019 in most cases. And a proportion of missed cases as high as 99%.

“As evidence, E, we considered the cumulative number of SARS-CoV-2 cases internationally imported from China up to January 21, 2020″

The model behind remain a classical SLIR model but with a discrete and stochastic dynamical and a geographical compartmentalization based on a Voronoi tessellation centred at airports, commuting intensity and population density. Interventions by local and State authorities are also accounted for. The ABC version is a standard rejection algorithm with distance based on the evidence as quoted above. Which is a form of cdf distance (as in our Wasserstein ABC paper). For the posterior distribution of the IFR,  a second ABC algorithm uses the relative distance between observed and generated deaths (per country). The paper further investigates different introduction sources (countries) before local transmission was established. For instance, China is shown to be the dominant source for the first EU countries impacted by the pandemics such as Italy, UK, Germany, France and Spain. Using a “counterfactual scenario where the surveillance systems of the US states and European countries are imagined to operate at levels able to identify 50% of all imported and locally generated infections”, the authors conclude that

“broadening testing specifications could have considerably slowed the pandemic progression, buying considerable time to prepare mitigation responses.”

The [errors in the] error of truth [book review]

Posted in Books, Statistics, University life with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , , on August 10, 2021 by xi'an

OUP sent me this book, The error of truth by Steven Osterling, for review. It is a story about the “astonishing” development of quantitative thinking in the past two centuries. Unfortunately, I found it to be one of the worst books I have read on the history of sciences…

To start with the rather obvious part, I find the scholarship behind the book quite shoddy as the author continuously brings in items of historical tidbits to support his overall narrative and sometimes fills gaps on his own. It often feels like the material comes from Wikipedia, despite expressing a critical view of the on-line encyclopedia. The [long] quote below is presumably the most shocking historical blunder, as the terror era marks the climax of the French Revolution, rather than the last fight of the French monarchy. Robespierre was the head of the Jacobins, the most radical revolutionaries at the time, and one of the Assembly members who voted for the execution of Louis XIV, which took place before the Terror. And later started to eliminate his political opponents, until he found himself on the guillotine!

“The monarchy fought back with almost unimaginable savagery. They ordered French troops to carry out a bloody campaign in which many thousands of protesters were killed. Any peasant even remotely suspected of not supporting the government was brutally killed by the soldiers; many were shot at point-blank range. The crackdown’s most intense period was a horrific ten-month Reign of Terror (“la Terreur”) during which the government guillotined untold masses (some estimates are as high as 5,000) of its own citizens as a means to control them. One of the architects of the Reign of Terror was Maximilien Robespierre, a French nobleman and lifelong politician. He explained the government’s slaughter in unbelievable terms, as “justified terror . . . [and] an emanation of virtue” (quoted in Linton 2006). Slowly, however, over the next few years, the people gained control. In the end, many nobles, including King Louis XVI and his wife Marie-Antoinette, were themselves executed by guillotining”

Obviously, this absolute misinterpretation does not matter (very) much for the (hi)story of quantification (and uncertainty assessment), but it demonstrates a lack of expertise of the author. And sap whatever trust one could have in new details he brings to light (life?). As for instance when stating

“Bayes did a lot of his developmental work while tutoring students in local pubs. He was a respected teacher. Taking advantage of his immediate resources (in his circumstance, a billiard table), he taught his theorem to many.”

which does not sound very plausible. I never heard that Bayes had students  or went to pubs or exposed his result to many before its posthumous publication… Or when Voltaire (who died in 1778) is considered as seventeenth-century precursor of the Enlightenment. Or when John Graunt, true member of the Royal Society, is given as a member of the Académie des Sciences. Or when Quetelet is presented as French and as a student of Laplace.

The maths explanations are also puzzling, from the law of large numbers illustrated by six observations, and wrongly expressed (p.54) as

\bar{X}_n+\mu\qquad\text{when}\qquad n\longrightarrow\infty

to  the Saint-Petersbourg paradox being seen as inverse probability, to a botched description of the central limit theorem  (p.59), including the meaningless equation (p.60)

\gamma_n=\frac{2^{2n}}{\pi}\int_0^\pi~\cos^{2n} t\,\text dt

to de Moivre‘s theorem being given as Taylor’s expansion

f(z)=\sum_{n=0}^\infty \frac{f^{(n)}(a)}{n!}(z-a)^2

and as his derivation of the concept of variance, to another botched depiction of the difference between Bayesian and frequentist statistics, incl. the usual horror

P(68.5<70<71.5)=95%

to independence being presented as a non-linear relation (p.111), to the conspicuous absence of Pythagoras in the regression chapter, to attributing to Gauss the concept of a probability density (when Simpson, Bayes, Laplace used it as well), to another highly confusing verbal explanation of densities, including a potential confusion between different representations of a distribution (Fig. 9.6) and the existence of distributions other than the Gaussian distribution, to another error in writing the Gaussian pdf (p.157),

f(x)=\dfrac{e^{-(z-\mu)^2}\big/2\sigma^2}{\sigma\sqrt{2\pi}}

to yet another error in the item response probability (p.301), and.. to completely missing the distinction between the map and the territory, i.e., the probabilistic model and the real world (“Truth”), which may be the most important shortcoming of the book.

The style is somewhat heavy, with many repetitions about the greatness of the characters involved in the story, and some degree of license in bringing them within the narrative of the book. The historical determinism of this narrative is indeed strong, with a tendency to link characters more than they were, and to make them greater than life. Which is a usual drawback of such books, along with the profuse apologies for presenting a few mathematical formulas!

The overall presentation further has a Victorian and conservative flavour in its adoration of great names, an almost exclusive centering on Western Europe, a patriarchal tone (“It was common for them to assist their husbands in some way or another”, p.44; Marie Curie “agreed to the marriage, believing it would help her keep her laboratory position”, p.283), a defense of the empowerment allowed by the Industrial Revolution and of the positive sides of colonialism and of the Western expansion of the USA, including the invention of Coca Cola as a landmark in the march to Progress!, to the fall of the (communist) Eastern Block being attributed to Ronald Reagan, Karol Wojtyła, and Margaret Thatcher, to the Bell Curve being written by respected professors with solid scholarship, if controversial, to missing the Ottoman Enlightenment and being particularly disparaging about the Middle East, to dismissing Galton’s eugenism as a later year misguided enthusiasm (and side-stepping the issue of Pearson’s and Fisher’s eugenic views),

Another recurrent if minor problem is the poor recording of dates and years when introducing an event or a new character. And the quotes referring to the current edition or translation instead of the original year as, e.g., Bernoulli (1954). Or even better!, Bayes and Price (1963).

[Disclaimer about potential self-plagiarism: this post or an edited version will eventually appear in my Book Review section in CHANCE.]